gistfile1.cpp

char buffer[2048]; // our packet buffer

//
// say we have the following variables that we need to pack into our packet.
//
std::uint16_t ptype   = 101u;
bool          success = true;
char str[]    "hello world.";

//
// we pack them into the packet buffer here.
//
char * p = buffer; // get a pointer and use it as a cursor into the buffer. we start at the beginning of the buffer here.
std::memset(buffer, 0, sizeof buffer); // 0 the buffer. good habit.

// pack the ptype
std::uint16_t ptype_in_networkorder = htons(ptype); // convert integer to network order.
std::memcpy(p, &ptype_in_networkorder, sizeof ptype);
p += sizeof ptype; // increment our cursor.

// pack the bool flag
std::memcpy(p, &success, sizeof success);
p += sizeof success;

// pack the string. in this case we will pack the len too.
std::uint32_t len = htonl(strlen(str));
std::memcpy(p, &len, sizeof len);
p += sizeof len; // increment our cursor.
std::memcpy(p, str, strlen(str));
p += strlen(str);

//
// send off the packet
//
std::size_t packet_size = p - buffer;
::send(socket_fd, buffer, packet_size);


//
// Alternativelly if you use my packet class.
// this is how I do it in my code.
//
Packet p;
p << ptype << success << str; // everything is abstracted for me.
::send(socket_fd, p.getData(), p.getSize());
p.clear(); // ready for reuse.